kfence_object_start(9)

💅 kfence_object_start — ok so where does this KFENCE object actually start? 👑

Bestie, you're reading the kfence_object_start(9) page from the Kernel API Manual, and it's a short one but it's lowkey crucial, so stay with me 🫶

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✨ NAME ✨

kfence_object_start — find the beginning of a KFENCE object 🌸

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🎀 SYNOPSIS 🎀

void * kfence_object_start (const void *addr );

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🦋 ARGUMENTS 🦋

• addr — an address that lives inside a KFENCE-allocated object. Like, somewhere in there. You don't need it to be the start, that's literally the whole point 💅

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⭐ RETURN ⭐

It hands you back the address of the beginning of the object. The actual start. The main character position 👑

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💖 DESCRIPTION 💖

Okay so here's the tea ☕ — SL[AU]B-allocated objects are laid out within a page one by one, so it's easy peasy to calculate the beginning of an object given a pointer inside it and the object size. Math, but like, chill math.

The same is not true for KFENCE 😭 KFENCE places a single object at either end of the page — like, either the front or the back, no in-between, it's giving dramatic entrances only.

So this helper function exists to find the beginning of a KFENCE-allocated object, because you genuinely cannot just do the arithmetic yourself. That's the vibe. That's the job. Slay 🧚

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🔥 SEE ALSO 🔥

• Kernel file ./include/linux/kfence.h — the header itself, go read it iykyk 📖
• is_kfence_address(9)
• kfence_alloc_pool_and_metadata(9)
• kfence_init(9)
• kfence_shutdown_cache(9)
• kfence_alloc(9)
• kfence_ksize(9)
• __kfence_free(9)
• kfence_free(9)
• kfence_handle_page_fault(9)
• __kfence_obj_info(9)

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Bestie reminder: that's the whole friend group up there, so if you're poking at KFENCE stuff you're gonna want all of them in your tabs 💀

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And that's the page!! 🌈 No cap, it's a tiny one. This came to you from ./include/linux, dated October 2026, under the handle kfence_object_start(9) — mwah, bye bestie, go find those object starts 💜🎀✨